Struct PointerValuePair

pub struct PointerValuePair<T> { /* private fields */ }

A pair consisting of a raw pointer (*const T) and an integer value, packed so that it takes the size of a pointer.

It is implemented by packing the integer value in the low bits of the pointer that are known to be zero because of alignment constraints.

The size of the value that can be stored alongside the pointer is 3 bits for most types, but ultimately depends on the minimum alignment of T: for example, if mem::align_of::<T>() == 16 then 4 bits are available to store the value.

Notes

Pointers to zero-sized types do not have enough space to store any value, so it must be zero.

Implementations

impl<T> PointerValuePair<T>

pub fn new(ptr: *const T, value: usize) -> PointerValuePair<T>

Creates a new PointerValuePair from the given raw pointer and extra bits.

Panics

Panics if the pointer type *const T does not have enough available low bits to store the value.

pub const fn available_bits() -> u32

Returns the number of bits available to store the value.

pub const fn max_value() -> usize

Returns the maximum (inclusive) integer value that can be stored in the pointer.

pub const fn ptr(self) -> *const T

Returns the pointer.

pub const fn value(self) -> usize

Returns the value stored alongside the pointer.

Trait Implementations

impl<T> Clone for PointerValuePair<T>

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<T: Debug> Debug for PointerValuePair<T>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<T> Copy for PointerValuePair<T>